In article <Pine.ULT.3.91.950127151746.26088A-100000 at essex.hsc.colorado.edu>, kr
uged at ESSEX.HSC.COLORADO.EDU (Edward Krug) writes:
>>There are four concepts I wish to include in the ongoing free radical
>discussion.
> First is that the various free radical scavangers have
>preferential cell comparatments which limit the interactions they can
>affect. Vit. E for instance is preferentially located in the lipid
>membranes and hydrophobic areas, while Vit. C tends to localize in the
>hydrophylic regions. The number and type of free radical interactions
>in arm's reach is consequently reduced. A number and variety of
>antioxidants may be necessary to cover all the ongoing interactions.
>> Second, the handshake each free radical scavanger requires for
>accepting the wayward electrons is probably somewhat unique. There
>probably is not a scavanger "for all seasons", and therefore a panoply of
>antioxidants may be necessary to cover all free radical reactions.
>> Third, although scavangers may intercept much of the free
>radical "bombs" it is a rare biological system which is 100% efficient.
>In enzymology disulfide bonds are broken or oxidized during some
>purification steps and must be reduce or rejoined specifically to regain
>enzymatic function. Although scavangers may prevent some oxidation they
>probably do little to repair damage once it happens.
>> Fourth, time and time again nature has been shown to be even more
>concervative than American Republican Talk Show Hosts. The mechanisms
>evolved in the early sexually reproducing multicellular organisms for
>insuring a turnover of the members of the adult population have probably
>been retained over the millions of subsequent years. These probably have
>been modified, but probably retained in some form. Add to these new
>mechanisms as evolution increased the complexity of the organisms. For
>there to be more than five independent processes contributing to finite
>lifespan would surprise me little.
>> Summary? The elucidation of the free radical based organism
>damage will reach a point where only marginal improvement in some aspect
>of old age vitality is achieved by intercepting the free radicals.
>Replacement of declining hormone levels or trophic factors or increasing
>the number of controled cell doublings, or invoking the lost capacity of
>regeneration as in amphibians or some other venues will have to be
>employed to extend healthy lifespan.
> To think that just because a remedy dosen't produce a dramatic
>result in a complex system that it is not involved is faulty logic, just
>as saying that since a five legged stool dosen't fall down when you
>take any one of them away proves that the legs do not hold the stool up.
>> Conclusion/suggestions? Caloric restriction to date has produced
>the most dramatic life extension, but it achieves only an extension.
>This method has revealed that certain diseases are coincidental with ageing,
>but not essential. Although this old observation may not lead to a cure,
>it is extremely important for ageing theory purposes. The question
>becomes what continues to degrade the organism in the reduced calorie
>nutritional condition. Since not all free radicals derive from leaky
>mitochondria or other conditions found in the fat and sassy organism the
>best place to look for a larger life extension effect would be in the
>calorically restricted orgamism using an array of antioxidants and free
>radical scavangers.
>> I appologize for insulting anyones intelligence, but the
>discussion seemed to be getting too symplistic.
>>Edward C. Krug Ph.D. E-mail= kruged at essex.hsc.colorado.edu>303-270-7234 (vox), 303-270-8681 (fax) Univ. of Colorado Med. School
>>Intelligent men will view no insult. Your concept of repair being more
important than antioxidants makes sense. If the repair process could
be improved then more damage from oxidants could be tolerated.
The controller of repair may be the penal gland.
Ron Blue